A novel patty of plastic food material, such as ground meat and the like, as well as novel methods and apparatus for forming the patty, have been developed wherein, inter alia, the food material is forced through cavities or apertures of a foraminous member into a mold to form a patty in which the food material defines interstitial voids for entrapping air and providing retention of cooking juices to promote more rapid and uniform cooking of the patty. Such methods and apparatus are disclosed in the Harry H. Holly U.S. Pat. Nos. 4,272,864 and 4,338,702.
The U.S. Pat. Nos. 4,356,595 and 4,372,008 to Sandberg et al. disclose apparatus for forming a meat patty by forcing ground meat under pressure through a foraminous member which defines a plurality of orifices.
When food material that contains tissue fibers, especially meat and the like, is forced through a foraminous member, opposite end portions of a single tissue fiber can be forced into different apertures in the foraminous member. The fibers, being stringy and thin, are not easily severed under the influence of conventional molding pressures.
A number of such fibers may be forced against the upstream side of the foraminous member in a manner that tends to plug up the foraminous member apertures. This tendency of tissue fibers to plug up foraminous member apertures was identified by Harry H. Holly and is described in detail in the above-identified U.S. Pat. No. 4,272,864 with reference to FIG. 23 of that patent.
Some of the apparatus and methods disclosed in some of the above-discussed U.S. patents are intended to function, at least with certain types of food material, so as to minimize or prevent the plugging up of the foraminous member with tissue fibers on the upstream side of the foraminous member. However, it would be desirable to provide a less complex method and apparatus for preventing plugging by tissue fibers, as well as to provide a method and apparatus that would be very effective with a great many types of food material.
Further, it would be beneficial if such an improved method and apparatus could be effected with a minimum of movement of the food material so as to avoid the undesirable effects of excessive working of the food material. Excessive working of some types of food material, such as ground beef, can make the food material less tender.
Finally, it would be advantageous if apparatus could be provided for quickly and easily converting conventional patty molding machines to the improved type of molding machine wherein the food material is forced through a foraminous member and wherein the "conversion" apparatus has the capability for dislodging tissue fibers from the upstream side of the foraminous member so as to avoid or minimize plugging up of the apparatus.